1. Field of the Invention
The present invention generally relates to a lane detecting apparatus for detecting boundary lines drawn on a road based on images input from a camera mounted on a vehicle.
2. Description of the Related Art
Lane keeping assist (hereinafter referred to as “LKA”) control is performed by detecting the boundary lines (hereinafter also simply referred to as “lines”) that divide a road in accordance with input images of the road obtained by a camera and assisting the steering of the driver so that the vehicle is driven along a target traveling line positioned substantially at the center between the lines on both sides (left and right). For example, when the amount of deviation from the target traveling line increases, an assisting steering force for reducing the amount of deviation is supplied.
The line of a road is not always drawn as a straight line at an intersecting point or a junction, but can also be curved or bent. When such a line is detected in performing LKA control, an assisting steering force towards the bending direction is supplied even where the road extends in a straight direction. Therefore, there is proposed a technology of determining whether a detected line is a line for indicating a branching point for recognizing lines in correspondence with a branching point, etc., (for example, see Japanese Laid-Open Patent Application No. 2005-346382, hereinafter referred to as “Patent Document 1” and Japanese Laid-Open Patent Application No. 2005-346383, hereinafter referred to as “Patent Document 2”). With this technology, in a case where a line branching away from the traveling road is detected, an unnecessary assisting steering force can be prevented from being supplied by not referring to the detected line for a predetermined period.
However, a road may have other bent lines besides those indicating a branching point. For example, although a car pool lane has bent lines drawn at its exit part, it is difficult to apply the technologies disclosed in Patent Documents 1 or 2 to such a car pool lane.